Nowadays, the LED and OLED light source of quickly developing has advantages of long life, high energy saving and flexibly light adjusting. Although the life of the LED light source reaches to 100000 hours, there is not a high reliable lamp of 100000 hours. The existing LED lamp is of 3 to 5 years quality protection, because the life of the LED drive power corresponding to the LED light source can not reach the requirement. The existing fully developed and high quality of the LED drive power is provided with 3 years' quality assurance, fewer with 5 years' quality assurance. The life of the drive power is between 300000 to 500000 hours. The life of the drive power determines the life of the LED lamp. For a high reliable and long life LED lamp, the life of the LED light source is 100000 hours, but the life of the coupled drive power is only 500000 hours. It greatly reduces the utilization of the LED and rarely meets the requirement of the high reliable lamp of 100000 hours. If these lamps are end-of-life treated in advance by the user or the manufacturer, it leads to a high wasting of the LED and lamp housing and other durable resource. If these lamps are repaired, it takes a lot of manpower and material cost. Especially for lamps installed high or in certain places, it takes high maintenance cost, even that the maintenance cost will be higher that the overall cost of the lamp. These maintenance cost makes the energy saving effect greatly reduced.
The common structure of an LED drive power includes an EMI filter and an AC/DC constant current unit. the AC/DC constant current unit is consist of full-wave rectification unit, PFC power factor correction unit, DC/DC power unit controlled by PWM, secondary rectification filtering unit, constant current limited voltage control unit and feedback control loop unit. in these units, except that the EMI filter is passive and reliable without failure, other units are easily broken down. As there are many elements in the system and the circuits are interrelated, if an element is broken down, others will be broken down even several units. The diagnosis and maintenance of the failure are difficult.
These failures can be generally summed up as internal element with break or short, but the results to the output are the same: none output voltage or current. So that it can be determined that whether it is broken down or not from combining the input voltage of the mains supply and the output voltage and the current of the LED drive power. If the input voltage of the mains voltage is normal, so as the output voltage and current of the LED drive power, the LED drive power is normal working; if the mains supply is normal and the voltage and current of the LED drive power are not, it can be determined that the LED drive power is broken down.